Conventional methods of operation (or managing) various processes wherein at least one phenomenon which varies with time is dealt with--such as water treatment processes; river information processing processes; meteorological information processing processes; thermal, nuclear and hydraulic power generation processes; co-generation processes; chemical processes; biological processes, security/exchange information processing processes, and bank management information processing processes--are practiced using formula models which describe these processes.
It is however impossible to convert a process into a formula model unless casualities or causal relationships among a group of variables describing the process have been made clear. On the other hand, when a logical model such as the "if then" rules is employed without using a formula model, application of such a logical model is infeasible unless a causal relationship between causes and the corresponding results have been ascertained. Needless to say, even in the case of a fuzzy method which makes combined use of a formula model and a logical model, its application is impossible unless both the models are described. A judgment and/or an operation (management) has therefore been carried out in the light of precedence or past experiences in such cases. In unusual cases or the like where neither cause nor result is known, an operator has conducted the operation on the basis of the past phenomenological history or his memory. Accordingly, it has been difficult to conduct a good operation all the time.
Further, described generally, these methods have not yet permitted any automated modification of the model structure or elements (rule, etc.). It has hence been difficult to flexibly cope with an actual phenomenon which varies in time.